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Nitrogen-Doped Anatase Nanofibers Decorated with Noble Metal Nanoparticles for Photocatalytic Production of Hydrogen

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journal contribution
posted on 28.06.2011, 00:00 authored by Ming-Chung Wu, Jussi Hiltunen, András Sápi, Anna Avila, William Larsson, Hsueh-Chung Liao, Mika Huuhtanen, Géza Tóth, Andrey Shchukarev, Noémi Laufer, Ákos Kukovecz, Zoltán Kónya, Jyri-Pekka Mikkola, Riitta Keiski, Wei-Fang Su, Yang-Fang Chen, Heli Jantunen, Pulickel M. Ajayan, Robert Vajtai, Krisztián Kordás
We report the synthesis of N-doped TiO2 nanofibers and high photocatalytic efficiency in generating hydrogen from ethanol–water mixtures under UV-A and UV-B irradiation. Titanate nanofibers synthesized by hydrothermal method are annealed in air and/or ammonia to achieve N-doped anatase fibers. Depending on the synthesis route, either interstitial N atoms or new N–Ti bonds appear in the lattice, resulting in slight lattice expansion as shown by XPS and HR-TEM analysis, respectively. These nanofibers were then used as support for Pd and Pt nanoparticles deposited with wet impregnation followed by calcination and reduction. In the hydrogen generation tests, the N-doped samples were clearly outperforming their undoped counterparts, showing remarkable efficiency not only under UV-B but also with UV-A illumination. When 100 mg of catalyst (N-doped TiO2 nanofiber decorated with Pt nanoparticles) was applied to 1 L of water–ethanol mixture, the H2 evolution rates were as high as 700 μmol/h (UV-A) and 2250 μmol/h (UV-B) corresponding to photo energy conversion percentages of ∼3.6 and ∼12.3%, respectively.